How to Generate 10,000 Unique Random Integers in Java?

Generating Unique Random Numbers in Java

In the realm of programming, the generation of random numbers holds a significant place. However, when working with large datasets, it often becomes crucial to avoid repetitions within these random sequences. In Java, this can be achieved efficiently through various methods.

The question at hand revolves around generating 10,000 unique random integers between 0 and 9999. While the initial approach employing the Random class is functional, it permits the possibility of duplicates. Let us explore a solution that eliminates this issue, ensuring the exclusivity of each random number.

The key technique lies in utilizing the Collections class and its shuffle method. This method operates on an immutable list and generates a permuted version of the original contents. By leveraging this feature, we can transform an array of integers into a randomized order without the risk of repetition.

An implementation of this approach in Java could be as follows:

Integer[] arr = new Integer[10000];
for (int i = 0; i < arr.length; i++) {
    arr[i] = i;
}
Collections.shuffle(Arrays.asList(arr));

In this code, we initialize an array of 10,000 integers, with values ranging from 0 to 9999, and then shuffle the array using the Collections.shuffle method. This operation ensures that the order of elements in the array is randomized, guaranteeing the uniqueness of each random number.

By understanding and implementing these techniques, programmers can effectively generate sets of non-repeating random numbers in Java, empowering them to address a wide range of applications that require statistical sampling or random data generation.

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